1. Field of the Invention
The present invention relates to a system for determining whether a print sheet on which printing has been carried out is an original or a copy (this is referred to as original authentication hereinafter), and to the structural elements of this system.
2. Description of the Related Art
In recent years, various methods have been used for carrying out original authentication for materials which have been printed out. Examples of these methods include: 1. A method in which a special purpose blank printing paper is used, on which a pattern or mark appears when copying is carried out; 2. A method in which authenticating information for the printed original data is printed on the print sheet as a special mark such as a two dimensional bar code; and 3. A method in which information for certifying the original is printed as an electronic mark pattern on the entire surface of the print sheet.
Methods for embedding the electronic mark in the print sheet include the following known techniques:
Japanese Patent Application No. 2001-78006 “Embedding and Detection of Mark Information for Black and White Two-value Document Images”
Japanese Patent Application No. 2001-53954 “Information Embedding Device, Information Reading Device, Electronic Marking System, Information Reading Method and Recording Medium
Japanese Patent Application Laid-Open No. 9-179494 “Secret Information Recording Method”
Japanese Patent Application Laid-Open No. 10-200743 “Document Processing Device”
The following is an example in which the originality of a print sheet is authenticated using a simplified electronic mark technique. In this example, the information for authenticating the original is incorporated as an electronic mark in the original digital data, printed by the printer device and then read by a scanner or the like. FIG. 14 shows the overall structure of the original authentication device 50 in which the electronic mark is embedded in the print sheet by the printer device, and the electronic mark pattern is read by a scanner and the like and checking is thereby carried out. FIG. 15 is a block diagram of the print data creation portion 51 and the printer device 52 of the original authentication system 50 of FIG. 14. FIG. 16 is a block diagram of the detection device 53 of the original authentication system 50 of FIG. 14.
As shown in FIG. 14, the original authentication system 50 includes the print data creation portion 51, the printer device 52, and the checking device 53. The print data creation portion 51 creates a print pattern for prints having an electronic mark inserted in the digital data. The printer device 52 outputs the print which will become the original. When the print sheet is input into the checking device 53, the information detected from the electronic marking of the print sheet is output.
As shown in FIG. 15, the print data creation portion 51 includes the original data input end 501 and the mark information creation portion 101. The original data input end 501 inputs the data that is to be printed. The mark information creation portion 101 creates the electronic mark information to be input in the original data.
As shown in FIG. 15, the printer device 52 includes: the print data input end 502; the print sheet input end 503; the printing portion 102; and the print sheet output end 504. The print data input end 502 inputs a print pattern including electronic mark information to the printer device 52. The print sheet input end 503 feeds print paper to the printer device 52. The printing portion 102 prints the print data input from the print data input end 502 on the print sheet fed in from the print sheet input end 503. The print sheet output end 504 discharges the print sheet on which printing has been carried out by the printing portion 102.
As shown in FIG. 16, the checking device 53 includes: a print paper input end 601; a print sheet reading sensor 201; a mark information checking portion 202; and a mark check result output end 602. The print paper input end 601 feeds the print sheets to be verified to the checking device 53. The print sheet reading sensor 201 scans the print sheet fed in from the print paper input end 601, and reads the pattern printed thereon. The mark information checking portion 202 checks the electronic mark of the pattern read by the print sheet reading sensor 201. The mark check result output end 602 outputs the result of the mark checking by the mark information checking portion 202.
The operation of the original authentication system 50 having the above structure will be described in the following.
At the print data creation portion 51 data is input from the original data input end 501, and at the mark information creation portion 101, electronic mark information for data is created. Both sets of data are incorporated and print data having mark information is thereby created. The electronic mark information which is inserted may be data certifying the print data, or information about time and date of creation or printing.
The print data that is created is input from the print data input end 502 to the printer device 52. At the printer device 52, print data including mark information is printed on the print sheet fed in from the print sheet input end 503, by the printing portion 102. The print sheet on which printing is carried out is discharged from the print sheet output end 504.
When the print sheet is input from the print paper input end 601, the print sheet reading sensor 201 scans the print sheet and creates a print pattern. The mark information checking portion 202 reads the mark information of the print pattern that has been created and sends the results to the mark check result output end 602.
It is to be noted that in general, when digital data is printed on print paper, deterioration in quality such as fading and the like, occurs due to various conditions such as the remaining toner amount, paper quality, humidity and the like. Because this deterioration occurs, in the method where the electronic mark information is incorporated in the digital information prior to printing, and then printed thereafter, it is difficult to determine whether the deterioration in quality occurred the time when the original was printed out (for the first time), or if the deterioration was a result of improper scanning, copying or the like. As a result determining if a print sheet was a copy or original (original authentication) was difficult.